529 lines
15 KiB
C
529 lines
15 KiB
C
/*
|
|
* Copyright (c) 1989, 1990, 1991, 1992 William F. Jolitz, TeleMuse
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. All advertising materials mentioning features or use of this software
|
|
* must display the following acknowledgement:
|
|
* This software is a component of "386BSD" developed by
|
|
* William F. Jolitz, TeleMuse.
|
|
* 4. Neither the name of the developer nor the name "386BSD"
|
|
* may be used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS A COMPONENT OF 386BSD DEVELOPED BY WILLIAM F. JOLITZ
|
|
* AND IS INTENDED FOR RESEARCH AND EDUCATIONAL PURPOSES ONLY. THIS
|
|
* SOFTWARE SHOULD NOT BE CONSIDERED TO BE A COMMERCIAL PRODUCT.
|
|
* THE DEVELOPER URGES THAT USERS WHO REQUIRE A COMMERCIAL PRODUCT
|
|
* NOT MAKE USE OF THIS WORK.
|
|
*
|
|
* FOR USERS WHO WISH TO UNDERSTAND THE 386BSD SYSTEM DEVELOPED
|
|
* BY WILLIAM F. JOLITZ, WE RECOMMEND THE USER STUDY WRITTEN
|
|
* REFERENCES SUCH AS THE "PORTING UNIX TO THE 386" SERIES
|
|
* (BEGINNING JANUARY 1991 "DR. DOBBS JOURNAL", USA AND BEGINNING
|
|
* JUNE 1991 "UNIX MAGAZIN", GERMANY) BY WILLIAM F. JOLITZ AND
|
|
* LYNNE GREER JOLITZ, AS WELL AS OTHER BOOKS ON UNIX AND THE
|
|
* ON-LINE 386BSD USER MANUAL BEFORE USE. A BOOK DISCUSSING THE INTERNALS
|
|
* OF 386BSD ENTITLED "386BSD FROM THE INSIDE OUT" WILL BE AVAILABLE LATE 1992.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE DEVELOPER ``AS IS'' AND
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE DEVELOPER BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*
|
|
* This procedure implements a minimal program execution facility for
|
|
* 386BSD. It interfaces to the BSD kernel as the execve system call.
|
|
* Significant limitations and lack of compatiblity with POSIX are
|
|
* present with this version, to make its basic operation more clear.
|
|
*
|
|
* PATCHES MAGIC LEVEL PATCH THAT GOT US HERE
|
|
* -------------------- ----- ----------------------
|
|
* CURRENT PATCH LEVEL: 3 00069
|
|
* -------------------- ----- ----------------------
|
|
*
|
|
* 05 Aug 92 Paul Kranenburg Fixed #! as a magic number
|
|
* 29 Jul 92 Mark Tinguely Fixed execute permission enforcement
|
|
* 15 Aug 92 Terry Lambert Fixed CMOS RAM size bug
|
|
* 12 Dec 92 Julians Elischer Place argc into user address space
|
|
* correctly
|
|
*/
|
|
|
|
#include "param.h"
|
|
#include "systm.h"
|
|
#include "signalvar.h"
|
|
#include "resourcevar.h"
|
|
#include "proc.h"
|
|
#include "mount.h"
|
|
#include "namei.h"
|
|
#include "vnode.h"
|
|
#include "file.h"
|
|
#include "exec.h"
|
|
#include "stat.h"
|
|
#include "wait.h"
|
|
#include "mman.h"
|
|
#include "malloc.h"
|
|
|
|
#include "vm/vm.h"
|
|
#include "vm/vm_param.h"
|
|
#include "vm/vm_map.h"
|
|
#include "vm/vm_kern.h"
|
|
|
|
#include "machine/reg.h"
|
|
|
|
extern int dostacklimits;
|
|
#define copyinoutstr copyinstr
|
|
|
|
/*
|
|
* execve() system call.
|
|
*/
|
|
|
|
/* ARGSUSED */
|
|
execve(p, uap, retval)
|
|
struct proc *p;
|
|
register struct args {
|
|
char *fname;
|
|
char **argp;
|
|
char **envp;
|
|
} *uap;
|
|
int *retval;
|
|
{
|
|
register struct nameidata *ndp;
|
|
struct nameidata nd;
|
|
char **argbuf, **argbufp, *stringbuf, *stringbufp;
|
|
char **vectp, *ep;
|
|
int needsenv, limitonargs, stringlen, addr, size, len,
|
|
rv, amt, argc, tsize, dsize, bsize, cnt, foff;
|
|
struct vattr attr;
|
|
struct vmspace *vs;
|
|
caddr_t newframe;
|
|
char shellname[MAXINTERP]; /* 05 Aug 92*/
|
|
long magic;
|
|
union {
|
|
char ex_shell[MAXINTERP]; /* #! and interpreter name */
|
|
struct exec ex_hdr;
|
|
} exdata;
|
|
int indir = 0;
|
|
|
|
/*
|
|
* Step 1. Lookup filename to see if we have something to execute.
|
|
*/
|
|
ndp = &nd;
|
|
ndp->ni_segflg = UIO_USERSPACE;
|
|
ndp->ni_dirp = uap->fname;
|
|
|
|
again: /* 05 Aug 92*/
|
|
ndp->ni_nameiop = LOOKUP | LOCKLEAF | FOLLOW | SAVENAME;
|
|
|
|
/* is it there? */
|
|
if (rv = namei(ndp, p))
|
|
return (rv);
|
|
|
|
/* does it have any attributes? */
|
|
rv = VOP_GETATTR(ndp->ni_vp, &attr, p->p_ucred, p);
|
|
if (rv)
|
|
goto exec_fail;
|
|
|
|
if (ndp->ni_vp->v_mount->mnt_flag & MNT_NOEXEC) { /* no exec on fs ?*/
|
|
rv = EACCES;
|
|
goto exec_fail;
|
|
}
|
|
|
|
/* is it executable, and a regular file? */
|
|
if ((ndp->ni_vp->v_mount->mnt_flag & MNT_NOEXEC) || /* 29 Jul 92*/
|
|
(VOP_ACCESS(ndp->ni_vp, VEXEC, p->p_ucred, p)) ||
|
|
((attr.va_mode & 0111) == 0) ||
|
|
(attr.va_type != VREG)) {
|
|
rv = EACCES;
|
|
goto exec_fail;
|
|
}
|
|
|
|
/*
|
|
* Step 2. Does the file contain a format we can
|
|
* understand and execute
|
|
*
|
|
* XXX 05 Aug 92
|
|
* Read in first few bytes of file for segment sizes, magic number:
|
|
* ZMAGIC = demand paged RO text
|
|
* QMAGIC = "compact" demand paged RO text
|
|
* (first page unmapped, a.out header in text section)
|
|
* Also an ASCII line beginning with #! is
|
|
* the file name of a ``shell'' and arguments may be prepended
|
|
* to the argument list if given here.
|
|
*/
|
|
exdata.ex_shell[0] = '\0'; /* for zero length files */
|
|
|
|
rv = vn_rdwr(UIO_READ, ndp->ni_vp, (caddr_t)&exdata, sizeof(exdata),
|
|
0, UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &amt, p);
|
|
|
|
/* big enough to hold a header? */
|
|
if (rv)
|
|
goto exec_fail;
|
|
|
|
/* ... that we recognize? */
|
|
rv = ENOEXEC;
|
|
magic = exdata.ex_hdr.a_magic;
|
|
|
|
/*
|
|
* XXX We should call a machine-dependent function
|
|
* to determine what to do with an executable.
|
|
*/
|
|
if (magic != ZMAGIC && magic != QMAGIC) {
|
|
char *cp, *sp;
|
|
|
|
if (exdata.ex_shell[0] != '#' ||
|
|
exdata.ex_shell[1] != '!' || indir) {
|
|
rv = ENOEXEC;
|
|
goto exec_fail;
|
|
}
|
|
for (cp = &exdata.ex_shell[2];; ++cp) {
|
|
if (cp >= &exdata.ex_shell[MAXINTERP]) {
|
|
rv = ENOEXEC;
|
|
goto exec_fail;
|
|
}
|
|
if (*cp == '\n') {
|
|
*cp = '\0';
|
|
break;
|
|
}
|
|
if (*cp == '\t')
|
|
*cp = ' ';
|
|
}
|
|
cp = &exdata.ex_shell[2]; /* get shell interpreter name */
|
|
while (*cp == ' ')
|
|
cp++;
|
|
|
|
sp = shellname;
|
|
while (*cp && *cp != ' ')
|
|
*sp++ = *cp++;
|
|
*sp = '\0';
|
|
|
|
indir = 1; /* indicate this is a script file */
|
|
vput(ndp->ni_vp);
|
|
FREE(ndp->ni_pnbuf, M_NAMEI);
|
|
|
|
ndp->ni_dirp = shellname; /* find shell interpreter */
|
|
ndp->ni_segflg = UIO_SYSSPACE;
|
|
goto again;
|
|
}
|
|
|
|
/* sanity check "ain't not such thing as a sanity clause" -groucho */
|
|
rv = ENOMEM;
|
|
if (/*exdata.ex_hdr.a_text == 0 || */ exdata.ex_hdr.a_text > MAXTSIZ ||
|
|
exdata.ex_hdr.a_text % NBPG || exdata.ex_hdr.a_text > attr.va_size)
|
|
goto exec_fail;
|
|
|
|
if (exdata.ex_hdr.a_data == 0 || exdata.ex_hdr.a_data > DFLDSIZ
|
|
|| exdata.ex_hdr.a_data > attr.va_size
|
|
|| exdata.ex_hdr.a_data + exdata.ex_hdr.a_text > attr.va_size)
|
|
goto exec_fail;
|
|
|
|
if (exdata.ex_hdr.a_bss > MAXDSIZ)
|
|
goto exec_fail;
|
|
|
|
if (exdata.ex_hdr.a_text + exdata.ex_hdr.a_data + exdata.ex_hdr.a_bss > MAXTSIZ + MAXDSIZ)
|
|
goto exec_fail;
|
|
|
|
if (exdata.ex_hdr.a_data + exdata.ex_hdr.a_bss > p->p_rlimit[RLIMIT_DATA].rlim_cur)
|
|
goto exec_fail;
|
|
|
|
if (exdata.ex_hdr.a_entry > exdata.ex_hdr.a_text + exdata.ex_hdr.a_data)
|
|
goto exec_fail;
|
|
|
|
/*
|
|
* Step 3. File and header are valid. Now, dig out the strings
|
|
* out of the old process image.
|
|
*/
|
|
|
|
/*
|
|
* We implement a single-pass algorithm that builds a new stack
|
|
* frame within the address space of the "old" process image,
|
|
* avoiding the second pass entirely. Thus, the new frame is
|
|
* in position to be run. This consumes much virtual address space,
|
|
* and two pages more of 'real' memory, such are the costs.
|
|
* [Also, note the cache wipe that's avoided!]
|
|
*/
|
|
|
|
/* create anonymous memory region for new stack */
|
|
vs = p->p_vmspace;
|
|
if ((unsigned)vs->vm_maxsaddr + MAXSSIZ < USRSTACK)
|
|
newframe = (caddr_t) USRSTACK - MAXSSIZ;
|
|
else
|
|
vs->vm_maxsaddr = newframe = (caddr_t) USRSTACK - 2*MAXSSIZ;
|
|
|
|
/* don't do stack limit checking on traps temporarily XXX*/
|
|
dostacklimits = 0;
|
|
|
|
rv = vm_allocate(&vs->vm_map, &newframe, MAXSSIZ, FALSE);
|
|
if (rv) goto exec_fail;
|
|
|
|
/* allocate string buffer and arg buffer */
|
|
argbuf = (char **) (newframe + MAXSSIZ - 3*ARG_MAX);
|
|
stringbuf = stringbufp = ((char *)argbuf) + 2*ARG_MAX;
|
|
argbufp = argbuf;
|
|
|
|
/* first, do args */
|
|
vectp = uap->argp;
|
|
needsenv = 1;
|
|
limitonargs = ARG_MAX;
|
|
cnt = 0;
|
|
|
|
/* first, do (shell name if any then) args */
|
|
if (indir) {
|
|
ep = shellname;
|
|
twice:
|
|
if (ep) {
|
|
/* did we outgrow initial argbuf, if so, die */
|
|
if (argbufp >= (char **)stringbuf) {
|
|
rv = E2BIG;
|
|
goto exec_dealloc;
|
|
}
|
|
|
|
if (rv = copyoutstr(ep, stringbufp,
|
|
(u_int)limitonargs, (u_int *)&stringlen)) {
|
|
if (rv == ENAMETOOLONG)
|
|
rv = E2BIG;
|
|
goto exec_dealloc;
|
|
}
|
|
suword(argbufp++, (int)stringbufp);
|
|
cnt++;
|
|
stringbufp += stringlen;
|
|
limitonargs -= stringlen;
|
|
}
|
|
|
|
if (indir) {
|
|
indir = 0;
|
|
/* orginal executable is 1st argument with scripts */
|
|
ep = uap->fname;
|
|
goto twice;
|
|
}
|
|
/* terminate in case no more args to script */
|
|
suword(argbufp, 0);
|
|
if (vectp = uap->argp) vectp++; /* manually doing the first
|
|
argument with scripts */
|
|
}
|
|
|
|
do_env_as_well:
|
|
if(vectp == 0) goto dont_bother;
|
|
|
|
/* for each envp, copy in string */
|
|
do {
|
|
/* did we outgrow initial argbuf, if so, die */
|
|
if (argbufp == (char **)stringbuf) {
|
|
rv = E2BIG;
|
|
goto exec_dealloc;
|
|
}
|
|
|
|
/* get an string pointer */
|
|
ep = (char *)fuword(vectp++);
|
|
if (ep == (char *)-1) {
|
|
rv = EFAULT;
|
|
goto exec_dealloc;
|
|
}
|
|
|
|
/* if not a null pointer, copy string */
|
|
if (ep) {
|
|
if (rv = copyinoutstr(ep, stringbufp,
|
|
(u_int)limitonargs, (u_int *) &stringlen)) {
|
|
if (rv == ENAMETOOLONG)
|
|
rv = E2BIG;
|
|
goto exec_dealloc;
|
|
}
|
|
suword(argbufp++, (int)stringbufp);
|
|
cnt++;
|
|
stringbufp += stringlen;
|
|
limitonargs -= stringlen;
|
|
} else {
|
|
suword(argbufp++, 0);
|
|
break;
|
|
}
|
|
} while (limitonargs > 0);
|
|
|
|
dont_bother:
|
|
if (limitonargs <= 0) {
|
|
rv = E2BIG;
|
|
goto exec_dealloc;
|
|
}
|
|
|
|
/* have we done the environment yet ? */
|
|
if (needsenv) {
|
|
/* remember the arg count for later */
|
|
argc = cnt;
|
|
vectp = uap->envp;
|
|
needsenv = 0;
|
|
goto do_env_as_well;
|
|
}
|
|
|
|
/* At this point, one could optionally implement a
|
|
* second pass to condense the strings, arguement vectors,
|
|
* and stack to fit the fewest pages.
|
|
*
|
|
* One might selectively do this when copying was cheaper
|
|
* than leaving allocated two more pages per process.
|
|
*/
|
|
|
|
/* stuff arg count on top of "new" stack */
|
|
/* argbuf[-1] = (char *)argc;*/
|
|
suword(argbuf-1,argc);
|
|
|
|
/*
|
|
* Step 4. Build the new processes image.
|
|
*
|
|
* At this point, we are committed -- destroy old executable!
|
|
*/
|
|
|
|
/* blow away all address space, except the stack */
|
|
rv = vm_deallocate(&vs->vm_map, 0, USRSTACK - 2*MAXSSIZ);
|
|
if (rv)
|
|
goto exec_abort;
|
|
|
|
/* destroy "old" stack */
|
|
if ((unsigned)newframe < USRSTACK - MAXSSIZ) {
|
|
rv = vm_deallocate(&vs->vm_map, USRSTACK - MAXSSIZ, MAXSSIZ);
|
|
if (rv)
|
|
goto exec_abort;
|
|
} else {
|
|
rv = vm_deallocate(&vs->vm_map, USRSTACK - 2*MAXSSIZ, MAXSSIZ);
|
|
if (rv)
|
|
goto exec_abort;
|
|
}
|
|
|
|
/* build a new address space */
|
|
addr = 0;
|
|
|
|
/* screwball mode -- special case of 413 to save space for floppy */
|
|
if (exdata.ex_hdr.a_text == 0) {
|
|
foff = tsize = 0;
|
|
exdata.ex_hdr.a_data += exdata.ex_hdr.a_text;
|
|
} else {
|
|
tsize = roundup(exdata.ex_hdr.a_text, NBPG);
|
|
/*
|
|
* QMAGIC starts mapping in at the beginning
|
|
* of the file; ZMAGIC skips the header.
|
|
*/
|
|
foff = (magic == ZMAGIC ? NBPG : 0);
|
|
}
|
|
|
|
/* treat text and data in terms of integral page size */
|
|
dsize = roundup(exdata.ex_hdr.a_data, NBPG);
|
|
bsize = roundup(exdata.ex_hdr.a_bss + dsize, NBPG);
|
|
bsize -= dsize;
|
|
|
|
/* map text & data in file, as being "paged in" on demand */
|
|
rv = vm_mmap(&vs->vm_map, &addr, tsize+dsize, VM_PROT_ALL, VM_PROT_DEFAULT,
|
|
MAP_FILE|MAP_COPY|MAP_FIXED, (caddr_t)ndp->ni_vp, foff);
|
|
if (rv)
|
|
goto exec_abort;
|
|
|
|
/* mark pages r/w data, r/o text */
|
|
if (tsize) {
|
|
/*
|
|
* QMAGIC starts at one page, ZMAGIC at 0.
|
|
*/
|
|
addr = (magic == QMAGIC ? NBPG : 0);
|
|
rv = vm_protect(&vs->vm_map, addr, tsize, FALSE,
|
|
VM_PROT_READ|VM_PROT_EXECUTE);
|
|
if (rv)
|
|
goto exec_abort;
|
|
}
|
|
|
|
/* create anonymous memory region for bss */
|
|
/* We need to take QMAGIC's offset into account, or else get abort */
|
|
addr = dsize + tsize + (magic == QMAGIC ? NBPG : 0);
|
|
rv = vm_allocate(&vs->vm_map, &addr, bsize, FALSE);
|
|
if (rv)
|
|
goto exec_abort;
|
|
|
|
/*
|
|
* Step 5. Prepare process for execution.
|
|
*/
|
|
|
|
/* touchup process information -- vm system is unfinished! */
|
|
vs->vm_tsize = tsize/NBPG; /* text size (pages) XXX */
|
|
vs->vm_dsize = (dsize+bsize)/NBPG; /* data size (pages) XXX */
|
|
/* user virtual address of text XXX */
|
|
vs->vm_taddr = (magic == QMAGIC ? NBPG : 0);
|
|
/* user virtual address of data XXX */
|
|
vs->vm_daddr = (caddr_t)tsize + (magic == QMAGIC ? NBPG : 0);
|
|
vs->vm_maxsaddr = newframe; /* user VA at max stack growth XXX */
|
|
vs->vm_ssize = ((unsigned)vs->vm_maxsaddr + MAXSSIZ
|
|
- (unsigned)argbuf)/ NBPG + 1; /* stack size (pages) */
|
|
dostacklimits = 1; /* allow stack limits to be enforced XXX */
|
|
|
|
/* close files on exec, fixup signals */
|
|
fdcloseexec(p);
|
|
execsigs(p);
|
|
|
|
/* name this process - nameiexec(p, ndp) */
|
|
len = MIN(ndp->ni_namelen,MAXCOMLEN);
|
|
bcopy(ndp->ni_ptr, p->p_comm, len);
|
|
p->p_comm[len] = 0;
|
|
|
|
/* mark as executable, wakeup any process that was vforked and tell
|
|
* it that it now has it's own resources back */
|
|
p->p_flag |= SEXEC;
|
|
if (p->p_pptr && (p->p_flag & SPPWAIT)) {
|
|
p->p_flag &= ~SPPWAIT;
|
|
wakeup(p->p_pptr);
|
|
}
|
|
|
|
/* implement set userid/groupid */
|
|
if ((attr.va_mode&VSUID) && (p->p_flag & STRC) == 0) {
|
|
p->p_ucred = crcopy(p->p_ucred);
|
|
p->p_cred->p_svuid = p->p_ucred->cr_uid = attr.va_uid;
|
|
}
|
|
if ((attr.va_mode&VSGID) && (p->p_flag & STRC) == 0) {
|
|
p->p_ucred = crcopy(p->p_ucred);
|
|
p->p_cred->p_svgid = p->p_ucred->cr_groups[0] = attr.va_gid;
|
|
}
|
|
|
|
/* setup initial register state */
|
|
p->p_regs[SP] = (unsigned) (argbuf - 1);
|
|
setregs(p, exdata.ex_hdr.a_entry);
|
|
|
|
ndp->ni_vp->v_flag |= VTEXT; /* mark vnode pure text */
|
|
|
|
vput(ndp->ni_vp);
|
|
FREE(ndp->ni_pnbuf, M_NAMEI);
|
|
|
|
/* if tracing process, pass control back to debugger so breakpoints
|
|
can be set before the program "runs" */
|
|
if (p->p_flag & STRC)
|
|
psignal(p, SIGTRAP);
|
|
|
|
return (0);
|
|
|
|
exec_dealloc:
|
|
/* remove interim "new" stack frame we were building */
|
|
vm_deallocate(&vs->vm_map, newframe, MAXSSIZ);
|
|
|
|
exec_fail:
|
|
dostacklimits = 1;
|
|
vput(ndp->ni_vp);
|
|
FREE(ndp->ni_pnbuf, M_NAMEI);
|
|
|
|
return(rv);
|
|
|
|
exec_abort:
|
|
/* sorry, no more process anymore. exit gracefully */
|
|
vm_deallocate(&vs->vm_map, newframe, MAXSSIZ);
|
|
vput(ndp->ni_vp);
|
|
FREE(ndp->ni_pnbuf, M_NAMEI);
|
|
exit(p, W_EXITCODE(0, SIGABRT));
|
|
|
|
/* NOTREACHED */
|
|
return(0);
|
|
}
|